Wireless devices have been in use for many years for enabling mobile communication of voice and data. Such devices can include mobile phones and wireless enabled personal digital assistants (PDA's) for example. FIG. 1 is a generic block diagram of the core components of a wireless device. The wireless device 10 includes a base band processor 12 for controlling application specific functions of the wireless device and for providing and receiving voice or data signals to and from a signal processing device, such as a radio frequency (RF) transceiver chip 14.
The RF transceiver 14 includes a communication core consisting of a transmitter core 22 and a receiver core 24. Generally, the RF transceiver 14 transforms data signals from one form to the other. For example, the transmitter core 22 is responsible for up-converting electromagnetic signals from base band to higher frequencies for transmission, while receiver core 24 is responsible for down-converting those high frequencies back to their original frequency band when they reach the receiver, processes known as up-conversion and down-conversion (or modulation and demodulation) respectively. The original (or base band) signal may be, for example, data, voice or video.
A peripheral circuit block 16 includes other components, such as for example low noise amplifiers for receiving wireless data from antenna 18, and power amplifiers for sending wireless data to antenna 18. There may be multiple low noise amplifiers and power amplifiers each calibrated, designed or configured to operate for a specific communications standard. For example, such communications standards include wireless communications standards such as the Global System for Mobile communications (GSM) standard and the Enhanced Data rates for GSM Evolution (EDGE) standard. It would be appreciated by a person skilled in the art that a single multi-standard compatible wireless device can include many such peripheral components. Accordingly, the transceiver 14 includes the necessary circuits for ensuring that the communication signals are properly transformed to meet the specifications of each standard. Therefore by example, the transceiver 14 can operate in the GSM or EDGE modes. The RF transceiver 14 and peripheral circuit block 16 are considered the radio system of the wireless device 10. Of course, other peripheral circuits not shown in FIG. 1 can be considered a peripheral component within peripheral circuit block 16. Those of skill in the art should understand that FIG. 1 is a simplified block diagram, and can include other functional blocks that may be necessary to enable proper operation or functionality of the wireless radio system 10.
In one configuration of wireless device 10, the peripheral circuits of the peripheral circuit block 16 are individually connected to the wireless device motherboard or daughterboard, and controlled by the baseband processor via control bus 20. In view of the number of available communication standards, more of such peripheral components are required, which can add complexity to the layout of the motherboard. Since each peripheral component is controlled independently (i.e. to turn it on/off for example), there will be a 1:1 ratio of base band processor pins to pins of the peripheral components and to interconnecting lines, where each control line controls the functionality or operation of each component. For example, if there are 8 peripheral components to be controlled, then the baseband processor will need to have 8 sets of physical pins, where each set includes any number of signal lines dedicated to control one of the peripheral components. Accordingly, conducting signal tracks are needed for connecting each control line to each peripheral component.
FIG. 2 is a drawing showing four amplifier circuits which are included in the front-end circuit 16 of FIG. 1, which can be all power amplifiers, all low noise amplifiers, or a mix of power amplifiers and low noise amplifiers, depending on the specific application. In FIG. 2, circuit chips 26, or dies are housed in its own package 28. Each package 28 includes by way of example, a reset pin R, an enable pin E, a signal input pin I, a signal output pin O, a ground pin VSS, and a positive voltage pin VDD. It is well known to the person skilled in the art that other control, signal and voltage pins can also be included depending on the function of the die. In the wireless device 10, each package 28 has its metal pin leads or ball grid array (BGA) bumps soldered to a printed circuit board (PCB), or a daughter board electrically coupled to the main PCB. As is known in the art, packages 24 are many times larger in size than the actual chips 26 enclosed therein. While not shown in FIG. 2, the outputs or inputs of one or more of the packages 28 are connected to an antenna switch that selectively couples one of the amplifier circuits to the antenna for either a receive or transmit operation. Accordingly, this antenna switch must also be controlled with knowledge of the specific amplifier circuit being enabled. In the present example with 4 control pins per package 28, there are 16 control signal and data pins that need to be connected to the base band processor 12. This does not include the additional pins of the antenna switch, which are also controlled by the base band processor 12.
Therefore, not only does the packaging 18 increase the required PCB space by virtue of its size, conductive tracks required for routing signals to each amplifier device will also consume PCB space. Furthermore, the length of the conductive tracks should be minimized to minimize wiring capacitance, which imposes design constraints for the layout of the amplifier devices. Thus, the complexity and size of the board they are installed on is increased.
In addition to controlling the numerous peripheral components, the baseband processor 12 is primarily responsible for processing data to be transmitted and data that is received, which requires significant processing capacity by the baseband processor 12 The baseband processor 12 can be implemented with a signal processing device, such as a digital signal processor (DSP) or a custom integrated circuit such as an application specific IC (ASIC). A DSP will already include a large number of pins, therefore it may not be possible to add more pins for controlling a large number of peripheral components. On the other hand, it may be too costly to customize an ASIC to include circuits and pins for controlling these peripheral components. Therefore, not only do additional peripheral components increase the form factor of portable wireless devices, controlling this increasing number of peripheral components in the radio system becomes increasingly complex.
It is, therefore, desirable to provide a wireless device with simplified control over the radio system, and in particular, the peripheral components of the radio system.